Molecular epidemiology of carbapenem-resistant hypervirulentKlebsiella pneumoniae: Risk factors and resistance mechanism of ceftazidime/avibactam in China

Abstract

The high morbidity and mortality rates associated with carbapenem-resistant hypervirulent Klebsiella pneumoniae have become a global public health problem. We analyzed the whole genome sequence and epidemiological data of 81 carbapenem-resistant Klebsiella pneumoniae strains and conducted sensitivity experiments to explore the optimal concentration of carbapenem-resistant Klebsiella pneumoniae. We verified the resistance and virulence genes of carbapenem-resistant Klebsiella pneumoniae using polymerase chain reaction and compared virulence between carbapenem-resistant hypervirulent Klebsiella pneumoniae andcarbapenem-resistant-non-hypervirulent Klebsiella pneumoniae through Galleria mellonella assays.The prevalent types of multilocus sequence typing and capsule serotypes in our carbapenem-resistant Klebsiella pneumoniae strains were ST11 (69.14%, 56/81). ST11-K64-O1/O2v1 has become an epidemic type in our hospital, with drug-resistance genes dominated by KPC-2 (90.12%, 73/81). Ceftazidime/avibactam has better antibacterial effects on carbapenem-resistant Klebsiella pneumoniae, and its resistance is mainly mediated by a resistance plasmid containing the blaKPC-2 gene. 52 carbapenem-resistant hypervirulent Klebsiella pneumoniae strains carry the blaKPC-2, with a high detection rate of siderophore. Further research has shown that the genetic environment of the blaKPC-2 contains TnpR_Tn3 and ISKpn27 upstream and ISKpn6 insertion sequences downstream. Galleria mellonella revealed that the survival rate of carbapenem-resistant hypervirulent Klebsiella pneumoniae was lower than that of carbapenem-resistant-non-hypervirulent Klebsiella pneumoniae, and the survival rate of carbapenem-resistant hypervirulent Klebsiella pneumoniae-K64 was lower than that of carbapenem-resistant hypervirulent Klebsiella pneumoniae-K47.The spread of carbapenem-resistant hypervirulent Klebsiella pneumoniae strains is alarming, necessitating molecular monitoring of hypervirulent strains and strengthening the nosocomial infection prevention and control measures. Antibiotics should be used reasonably based on patients' infection status and local epidemiological data.